WASHINGTON (AP) - If a 3-mile-wide rock from space smashed into the Atlantic
Ocean it would drown most of the upper East Coast in the largest tidal
wave in recorded history, a study finds.

Astrophysicist Jack Hills of the Los
Alamos National Laboratory, heading a team to investigate such things,
said Wednesday findings by his group leads to the conclusion that such
a disaster from outer space is not far-fetched.

Any 100-year period, a lifetime for many
people, has a 2 percent to 3 percent chance that an asteroid would splash
into either the Pacific or Atlantic ocean and cause widespread coastal
flooding.

An asteroid striking water at thousands
of miles an hour could send a 300-foot-tall wall of water racing across
the ocean at the speed of a jet plane, Hills said. The wave would stop
only after it smashed ashore, and as the water retreated over many square
miles, it would scour the land, rip apart buildings, erode vast areas.

The result, Hills said: disaster.

``The damage would be unprecedented in
human history,'' said Hills, speaking at the national meeting of the American
Astronomical Society. ``It would kill millions of people and cause billions
in damage.''

Based on computer simulations of what
would ensue if an asteroid smashed into the central Atlantic, Hills said
all of Delaware, Maryland and Virginia would be inundated. In New York,
Long Island and Manhattan would be swamped.

Florida would sustain little damage.
Hills said shallow water on a gently sloping continental shelf would protect
the Sunshine State. All except Miami, which lies on a deep bay that would
suddenly rise up and wash away the city.

Across the Atlantic, the coasts of France,
Portugal and part of Spain would be drowned. England, protected by a shallow
waters, would be little affected.

A Pacific Ocean asteroid strike midway
between Hawaii and San Francisco would launch an ocean wave that would
roll over much of Honolulu and flood the Los Angeles basin, bisecting Santa
Catalina Island. Across the Pacific, such a wave would wash away coastal
cities and towns in Japan, a country that already has lost thousands of
lives to tidal waves, or tsunamis, caused by earthquakes.

Hills estimated on the basis of his studies
that an asteroid more than 600 feet in diameter will strike one of the
Earth's oceans at least once every 3,000 to 5,000 years. If a person lives
for 100 years, then there is about one chance in 50 of being alive when
an asteroid tidal wave occurs, he said.

Hills said geologists have found evidence
of such occurrences in the past. The impact of an asteroid several miles
in diameter is thought to have helped wipe out the dinosaurs 65 million
years ago.

In Hawaii, geologists have found ocean
coral deposited on a hillside 90,000 years ago by a tsunami that may have
been 1,000 feet high.

Hills said that if an asteroid ocean
strike were detected, people would have no more than three hours' warning
before the mountain of water traveling hundreds of miles an hour rolled
over land.

Astronomical satellites possibly could
detect an approaching asteroid, said Hills, but current technology could
not prevent Earth from being smashed.